Back in December of 2011, Consumer Watchdog called on the EPA to investigate Hyundai over its fuel economy claims. According to Consumer Watchdog, Hyundai claimed that its Elantra was good for 29 mpg in the city and 40 mpg on highway. The problem the organization had with the claims is that it received a higher than usual number of complaints that real-world mileage was in the mid-20 mpg range.

The EPA did investigate Hyundai for misleading mileage claims as well as Kia, and changes in fuel economy estimates are coming as a result of the investigation. Both Kia and Hyundai will be lowering the fuel economy estimates on the majority of their 2012 to 2013 models after EPA testing discovered discrepancies between its data and the company's data.

Hyundai and Kia admitted to overstating the estimated fuel economy on window stickers of about 900,000 vehicles sold since late 2010. The two automakers will reportedly spend millions of dollars to compensate owners for faulty claims of economy.

Hyundai will also have to retract its widely used claim that it leads the industry with four vehicle models able to get 40 mpg on the highway. That statement will be retracted because estimated highway economy on the 2013 Accent, Veloster, and Elantra are being reduced to below 40 mpg.

Some of the biggest losers include the Hyundai Accent and the all-new, redesigned 2013 Hyundai Santa Fe. The Accent saw its 30/40/33 (city/highway/combined) rating drop to 28/37/31. The Santa Fe Sport (2WD) saw a huge drop in its highway rating, going from 21/31/25 (city/highway/combined) to 20/27/23.

Many of the mileage adjustments take Hyundai models from being class leaders to either middle-of-the-pack or lower.

On the Kia side of things, the Soul took the biggest hit as it saw its highway numbers drop by 6 mpg (35 mpg highway to 29 mpg highway).

Overstating fuel efficiency is a significant blunder by the two car companies because gas prices are up, and many people are shopping based on fuel economy claims by the manufacturer. The EPA notes that window sticker values have previously been reduced on only two vehicles sense 2000, so that makes Hyundai’s folly even more egregious.

"Given the importance of fuel efficiency to all of us, we're extremely sorry about these errors," said Hyundai Motor America President and CEO John Krafcik. "We're going to make this right."

Krafcik blamed the inaccurate fuel efficiency claims on "procedural errors" in the fuel-economy testing methodology the company used. Hyundai-Kia's combined fleetwide fuel economy average declined from 27 MPG to 26 mpg for the 2012 model year working out to about a 3% reduction.

Krafcik added, "We've identified the source of the discrepancies between our prior testing method and the EPA's recommended approach."

I own a 2011 Elantra and I don't get anywhere near the city mileage, however my previous vehicle I was getting better than highway mileage. This is going the same distance, in the same driving conditions, and same driving style.

The issues now is that manufactures "tune" their vehicles to get great fuel efficiency during the standardized tests, however in real world conditions the vehicles don't perform as well. Add in the "extra" features of the higher end model I wouldn't be surprised if that model performs significantly worse due to weight changes in the vehicle.

I didn't expect highway mileage when I purchased the vehicle since I live in Denver and have other conditions that cause the mileage to be less, however I didn't expect a 10+mpg drop in efficiency especially comparing my previous vehicle.

I guess since I leased the vehicle I will be able to get out of my lease based on mileage used. This happened before when there was a misstatement on my Nissan.

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